Inhibition of C5 convertase by epsilon amino caproic acid (EACA): a limiting factor in the generation of C5a anaphylatoxin. 1978

E H Vallota

The effect of EACA on spontaneous C5 consumption and on the mechanisms of C5 activation through the alternative pathway of complement were analyzed. In contrast to the effect upon C3, ADDITION OF 1 M EACA to normal human serum (NHS) did not enhance spontaneous consumption of C5, but augmented its haemolytic efficiency. In the presence of 1 M EACA, activation of serum with zymosan (Z), resulted in inhibition of the formation of C5 convertase, and thus of C5 cleavage and C5a anaphylatoxin release. The generation of a C5 convertase on activated zymosan (Z) was inhibited when Z was formed at 17 degrees with NHS containing 1 M EACA. In contrast, if Z was formed in the absence of EACA the C5 convertase could be regenerated with fresh serum containing 1M EACA. Nearly maximal C5 consumption was obtained if 5 mM EGTA and 10 mM MgCl2 were added to the mixture. These conditions are considered optimal for generation and maximum recovery of fully active anaphylatoxin.

UI MeSH Term Description Entries
D007122 Immunoelectrophoresis A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.
D008274 Magnesium A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D010452 Peptide Biosynthesis The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules. Biosynthesis, Peptide
D003166 Complement Activating Enzymes Enzymes that activate one or more COMPLEMENT PROTEINS in the complement system leading to the formation of the COMPLEMENT MEMBRANE ATTACK COMPLEX, an important response in host defense. They are enzymes in the various COMPLEMENT ACTIVATION pathways. Activating Enzymes, Complement,Enzymes, Complement Activating
D003176 Complement C3 A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase. C3 Complement,C3 Precursor,Complement 3,Complement C3 Precursor,Complement Component 3,Precursor-Complement 3,Pro-C3,Pro-Complement 3,C3 Precursor, Complement,C3, Complement,Complement, C3,Component 3, Complement,Precursor Complement 3,Precursor, C3,Precursor, Complement C3,Pro C3,Pro Complement 3
D003182 Complement C5 C5 plays a central role in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C5 is cleaved by C5 CONVERTASE into COMPLEMENT C5A and COMPLEMENT C5B. The smaller fragment C5a is an ANAPHYLATOXIN and mediator of inflammatory process. The major fragment C5b binds to the membrane initiating the spontaneous assembly of the late complement components, C5-C9, into the MEMBRANE ATTACK COMPLEX. C5 Complement,Complement 5,Complement C5, Precursor,Complement Component 5,Precursor C5,Pro-C5,Pro-complement 5,C5, Complement,C5, Precursor,C5, Precursor Complement,Complement, C5,Component 5, Complement,Precursor Complement C5,Pro C5,Pro complement 5
D004533 Egtazic Acid A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID. EGTA,Ethylene Glycol Tetraacetic Acid,EGATA,Egtazic Acid Disodium Salt,Egtazic Acid Potassium Salt,Egtazic Acid Sodium Salt,Ethylene Glycol Bis(2-aminoethyl ether)tetraacetic Acid,Ethylenebis(oxyethylenenitrile)tetraacetic Acid,GEDTA,Glycoletherdiamine-N,N,N',N'-tetraacetic Acid,Magnesium-EGTA,Tetrasodium EGTA,Acid, Egtazic,EGTA, Tetrasodium,Magnesium EGTA
D006461 Hemolysis The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity. Haemolysis,Extravascular Hemolysis,Intravascular Hemolysis,Extravascular Hemolyses,Haemolyses,Hemolyses, Extravascular,Hemolyses, Intravascular,Hemolysis, Extravascular,Hemolysis, Intravascular,Intravascular Hemolyses
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000614 Aminocaproates Amino derivatives of caproic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the amino caproic acid structure. Aminocaproic Acids,Aminocaproic Acid Derivatives,Aminohexanoates,Aminohexanoic Acid Derivatives,Aminohexanoic Acids,Acid Derivatives, Aminocaproic,Acid Derivatives, Aminohexanoic,Acids, Aminocaproic,Acids, Aminohexanoic,Derivatives, Aminocaproic Acid,Derivatives, Aminohexanoic Acid

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